1. Field of the Invention
The present invention relates to an information recording apparatus and a method thereof suitable for recording instrumental so that a series of data is successively supplied, for example, measured data.
2. Description of the Related Art
A driving device having a detachable cassette tape on which digital data is recorded is connected to a host computer through an interface and is used as an external storing device of a magnetic tape recording/reproducing apparatus (hereinafter, referred to as data recorder). As an example of the data recorder, a helical scan type recorder of which digital data is recorded to a cassette tape with a rotating head is known. Such a data recorder is connected to a host computer through an interface unit corresponding to for example SCSI (Small Computer System Interface) standard.
In addition to conventional data exchanged with a computer, such a data recorder handles instrumental data that is obtained by observing and instrumentation devices. Examples of instrumental data are data transmitted from a satellite and distortion data measured at a tunnel with an ultrasonic wave. In devices connected to respective data recorders disposed at several positions, vibrations of an explosion at a particular position are measured by the instrumental devices. Thus, a plurality of sequences of data are obtained. Such data is referred to as instrumental data. The data contains a large amount of noise. Thus, any parts of the data are discarded. In addition, the data is sequentially supplied to each data recorder.
FIG. 1 is a block diagram showing an example of the structure of a recording/reproducing system using a data recorder that records and/or reproduces instrumental data. In this example, data is received from a satellite and recorded to the data recorder. A radio wave transmitted from a satellite is received by an antenna 100. The received signal is supplied to a receiving system 101 and converted into digital data. The received data, which is instrumental data, is supplied from the receiving system 101 to a recording system 102. The recording system 102 adds particular additional information to the received data. The resultant data is supplied to a data recorder 103 and then recorded on a record tape 104.
When data is reproduced, the record tape 104 is attached to a data recorder 103. Instrumental data reproduced by the data recorder 103xe2x80x2 is supplied to a processing system 105. The data recorder 103xe2x80x2 may be the same as the data recorder 103 that is used for recording data. The processing system 105 converts the reproduced instrumental data in a predetermined format. The formatted data is stored as measured data to a storing system 106 that is for example a hard disk. The stored data is analyzed by for example a computer.
FIG. 2 is a block diagram showing an example of the structure of the recording system 102 and the data recorder 103 according to a related art reference. The received data supplied from the receiving system 101 to the recording system 102 is temporarily stored to a data buffer 110. A CPU 111 generates additional information corresponding to the instrumental data, controls the data buffer 110, controls the recording system 102, and generates a control command for the data recorder 103 (that will be described later).
After a predetermined amount of data is stored in the data buffer 110, data is swept out and supplied to an adding device 112. Likewise, the additional information is supplied from the CPU 111 to the adding device 112. The adding device 112 functions as a switching mechanism for selecting instrumental data received from the data buffer 110 or additional information received from the CPU 111 and outputs the instrumental data and the additional data with one line. The adding device 112 outputs the instrumental data and the header information as record data. The record data is output from a data connector 113 of the recording system 102 and supplies the record data to a data connector of the data receiver 103.
On the other hand, the CPU 111 generates a command for controlling the data recorder 103 and outputs the command from a command connector 114. This command is supplied to a relevant connector (command connector) of the data recorder 103. The data recorder 103 records the record data of which the instrumental data and the additional information have been combined to the record tape 104.
FIG. 3 is a schematic diagram showing an example of a record format in which instrumental data is recorded to the record tape 104. At the beginning of the tape 104, a lead area is formed for a predetermined length. Instrumental data starts from a point A that is the end of the lead area. The instrumental data is successively recorded to the record tape 104 until the data recorder 103 receives a stop command. The rest of the record tape 104 after the end of the instrumental data (this area is referred to as point B) is an unused area.
FIG. 4 is a flow chart showing an example of the process of the data recorder 103 that records instrumental data according to the related art reference. When the record tape 104 is attached to the data recorder 103 (at step S100), the tape 104 is moved to a write point (a point A shown in FIG. 3) (at step S101). When data is written to the tape 104 on which data has been written, the tape 104 is moved to the point B shown in FIG. 3.
When the data recorder 103 receives data, the data recorder 103 records the data from the write point (at step S102). After the recorder 103 has recorded the data to the tape 104 (at step S103), the tape 104 is moved to a header information write point. The tape 104 is manually moved by the user. For example, the header information write point is set adjacent to the data write end point. At step S105, the header information is written after the header information write point.
After the header information has been written to the tape 104, if there is next data (at step S107), the flow returns to step S101. At step S101, the tape 104 is manually moved. Thereafter, the next data and header information thereof are written to the tape 104. In such a manner, instrumental data and header information are paired. After data has been measured and all data has been written, the tape 104 is rewound to the top thereof (at step S108). Thereafter, the tape 104 is detached (at step S109).
FIG. 5 is a schematic diagram showing the format of the tape 104 in which instrumental data and additional information have been recorded in the above-described manner. Conventionally, pairs of additional information (header information) and instrumental data are successively recorded on the tape 104.
Header information is for example time information and position information corresponding to measured data. Thus, the header information varies time by time. For example, when data is received from a satellite, the data is measured when the satellite comes to a receivable range. After data is recorded for a predetermined time period (for example 10 minutes), the satellite leaves the receivable range. Thus, the measuring operation and the recording operation are stopped. Thereafter, header information of measured date and time is recorded. When the satellite comes to the receivable range next day, data is measured and recorded. Header information corresponding to the data is recorded in the same manner. The data write point and the header information write point of each session (for example, tape position information) should be recorded in a proper means like memo.
FIG. 6 is a flow chart showing an example of the process of the data recorder 103xe2x80x2 (or 103) that reproduces the above-described data from the record tape 104. When the record tape 104 is attached to the data recorder 103xe2x80x2 (at step S200), the tape 104 is moved to the header information read-out point (at step S201). The data recorder 103xe2x80x2 reads header information from the header information read-out point of the tape 104 (at step S202). The tape 104 is manually moved by the user with reference to the tape position information of the header write point that has been recorded.
After the data recorder 103xe2x80x2 has read the header information (at step S203), the tape 104 is moved to the data read-out point (at step S204). The data recorder 103xe2x80x2 reads the header information from the data read-out point of the tape 104 (at step S205). Since the header information does not contain the tape position information of the data read-out point, the tape 104 is manually moved by the user with reference to the tape position information of the data write point that has been recorded.
After the data has been read (at step S206), when the next data is read (at step S207), the flow returns to step S201. At step S201, the tape is manually moved. The data recorder 103 reads the next header information and the next data from the tape 104. After desired data has been read, the tape 104 is rewound to the beginning thereof (at step S208) and the tape 104 is detached (at step S209).
Conventionally, as described above, to process data recorded on the record tape 104, data recorded on the record tape 104 should be read from the top thereof to the end thereof with the same system as the writing system so as to format header information and index information. In other words, in the conventional recording method, pairs of instrumental data and header information are repeated in the order of the measurement. Thus, unless data is read from the top of the tape 104 to the end thereof, all the data on the tape 104 cannot be obtained.
In addition, in the related art reference, as described above, when instrumental data is recorded by the data recorder 103, the received data that is output from the recording system 102 is input by the data connector. On the other hand, the control command for controlling the data recorder 103 is input by the command connector. Although data is read from the data buffer, header information and a control command are generated and output by the CPU 111.
To write instrumental data and header information that represents the contents of the tape 104 to the tape 104, the recording system 102 should have a switching mechanism (the adding device 112 shown in FIG. 10) that selects output data of the data buffer 110 or a control command received from the CPU 111 so as to supply the header information and data to the data connector of the data recorder 103 (with one line).
Therefore, an object of the present invention is to provide an information recording apparatus and a method thereof that allow all data of instrumental data recorded on a tape to be obtained.
Another object of the present invention is to provide an information recording apparatus and a method thereof that allow both data that is output from a data buffer and header information that is output from a CPU to be recorded on a tape without need to use a switching mechanism.
A first aspect of the present invention is an information recording apparatus for recording a sequence of user data composed of a digital signal to a tape shaped record medium, comprising a boundary setting means for setting the boundary of a first area and a second area to the tape shaped record medium, the first area being used to record the user data, the second area being used to record header information containing at least the position information that represents the top of the user data, a first memory means for successively storing the user data in the order of which the user data is received, a second memory means for storing the header information formed corresponding to the user data, a recording means for reading the user data from the first memory means corresponding to a control signal, recording the user data to the first area, reading the header information from the second memory means, and recoding the header leader data to the second area in the order of which the user data is recorded to the first area, and a controlling means for generating the control signal.
The controlling means controls the recording means so as to record the position information of the boundary of the first area and the second area to the top portion of the second area.
The controlling means controls the recording means so as to read the header information from the second memory means, temporarily write the header information to the first memory means, read the header information from the first memory means, and record the header information to the second area.
The controlling means records the user data to the first area and then the header information to the second area.
The header information further contains time information of the user data.
The header information further contains identification information of the user data.
The position information is address information that represents the position in the longitudinal direction of the tape shaped record medium.
The user data is composed of instrumental data that is measured or observed in a time sequence.
A second aspect of the present invention is an information recording method for recording a sequence of user data composed of a digital signal to a tape shaped record medium, comprising the steps of (a) setting the boundary of a first area and a second area to the tape shaped record medium, the first area being used to record the user data, the second area being used to record header information containing at least the position information that represents the top of the user data, (b) successively storing the user data in the order of which the user data is received, (c) storing the header information formed corresponding to the user data, (d) reading the user data obtained at step (b) corresponding to a control signal, recording the user data to the first area, reading the header information obtained at step (c), and recoding the user data to the second area in the order of which the user data is recorded to the first area, and (e) generating the control signal.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of a best mode embodiment thereof, as illustrated in the accompanying drawings.